Facebook downplayed the seriousness of a recent security breach Friday, announcing that though it initially said 50 million people were affected, that number was actually closer to 30 million.

Facebook first spoke publicly about the attack two weeks ago, but in a release Friday, they detailed for the first time just how much information attackers were able to access.

According to the release, for about 15 million people, attackers accessed names and contact details (either phone, email, or both, depending on what was included on the account), and for about 14 million people, attackers accessed names and contact details as well as username, gender, locale/language, relationship status, religion, hometown, self-reported current city, birthdate, device types used to access Facebook, education, work, the last 10 places they checked into or were tagged in, website, people or Pages they follow, and the 15 most recent searches.

Attackers did not access information from about 1 million accounts.

Who might be behind the attack — or what they might do with the litany of stolen information — Facebook did not say.

“We’re cooperating with the FBI, which is actively investigating and asked us not to discuss who may be behind this attack,” Guy Rosen, Facebook’s VP of Product Management, said in a release Friday.

Facebook has repeatedly mishandled user data and downplayed the seriousness of security breaches in the past. According to a New York Times report from June, Facebook has allegedly shared user data with more than 60 device makers — including Apple, Microsoft and Samsung — over the last decade, allowing corporations access to extensive personal information.

Facebook has also been at the center of the Cambridge Analytica scandal, having shared user data with the company that reportedly allowed it to microtarget users on the platform during the 2016 presidential election.

The social network was similarly sluggish in revealing the extent of its data sharing, first saying 50 million people were affected and later saying it was actually 87 million.

“If [Zuckerberg] had gone immediately [after the scandal broke] up to Congress it would have been bad, now I think it’s gonna be horrific,” veteran political analyst Charlie Cook said at the time. “This poor guy’s gonna be walking into an ambush…It’s gonna be like Custer’s last stand.”